It’s interesting the chimps war on other chimp tribes. Also, this doesn’t have to be war…it can be competition for resources. Basically anything that makes higher levels of cooperation in a group out-compete other groups…though it’s unlikely that sharing Europe was entirely peaceful. Also, telling is the fact that the ‘love’ neurotransmitter also makes Thems more Them-like. Hard to see how that would come about without Thems being an active danger. I like the theories that we’re basically happy peaceful crew except for the distortion imposed by agriculture or cities or hierarchy (all the Gimbutas stuff) but have abandoned them over time as the evidence of history, prehistory, primatology, biochemistry, and mathematical modeling made them more and more implausible. Anway, I’ve laid out my case in the cited article and a few others. One that looks at competing theories for our eusociality. At some point, I might have the bandwidth to recap all that in dribs and drabs in the comments but this isn’t one of those weeks. I spent months writing (and a couple of decades researching) the 3 or 4 relevant Medium articles. I can’t really do better than that.
The upside is that we have the Chimp but also the Bonobo as close cousins and we have the ability to choose a bigger and bigger Us — since we’re going to need the biggest possible Us to make it through the upcoming narrows.
Just a PS, thought I’d do a quick Wikipedia check for the most recent numbers. https://en.wikipedia.org/wiki/Human_cannibalism. Probably not totally peaceful then.
There is evidence, both archaeological and genetic, that cannibalism has been practiced for hundreds of thousands of years by early Homo Sapiens and archaic hominins. Human bones that have been “de-fleshed” by other humans go back 600,000 years. The oldest Homo sapiens bones (from Ethiopia) show signs of this as well. Some anthropologists, such as Tim D. White, suggest that ritual cannibalism was common in human societies prior to the beginning of the Upper Paleolithic period. This theory is based on the large amount of “butchered human” bones found in Neanderthal and other Lower/Middle Paleolithic sites.